The present invention generally relates to avionics displays, and more particularly refers to backlighted LCDs, and even more particularly concerns improved fluorescent lamps for backlighted LCD avionics displays.
In today's aviation industry, it is common for an aircraft to be expected to perform in extreme thermal conditions. It is not uncommon for an aircraft to be flying at an altitude of 40,000 feet with an outside temperature of less than minus 40.degree. F. Similarly, it is not uncommon for an aircraft to sit overnight on a cold northern runway
One particular problem that must be addressed by avionics engineers is the difficulty in starting fluorescent lamps in extremely low temperatures.
In the past, it has been proposed that the fluorescent lamp tube be heated by running a current through a resistive element or heating wire element around disposed the tube. While this approach has enjoyed some success in the past, it has some drawbacks. Typically, the resistive heating element was wrapped around the outside of the tube and electrically connected to its current source by solder termination. This wire would be grouped with the filament wires of the lamp and together soldered to some wiring harness. Two problems occur in such designs. First of all, the heating element wire may be easily detached, resulting in loss of heating capability. Additionally, the soldering of that wire together with the filament wires results in protracted and labor intensive repair and maintenance practices.
Consequently, there exists a need for improvement in fluorescent lamps and their means for connection with the remainder of the avionics display system.